Mechanics of the Cephalopod Chromatophore Layer: Structural Characterization of Cephalopod Chromatophores

Cephalopods are a class of mollusks that include cuttlefish, octopus, and squid1 that are capable of adaptive display capabilities. The cephalopods unique adaptable appearance is enabled by a sequence of thin layers in their soft and stretchable skin2 that allows them to quickly change color (Figure 1a), pattern, iridescence and texture (with the exception of the squid)3. Two layers in the skin are responsible for this remarkable ability (Figure 1b). The chromatophore layer, located beneath the transparent epidermis layer, is a layer of thousands of pigmented chromatophore organs that are yellow, red, or brown. Below this layer is a sequence of structural reflectors called iridophores that reflect spectra from near-IR to short-wavelength blues and greens1,4. The combination of chromatophore pigments and structural reflectors allows the cephalopod to display dynamic patterning in complex combinations of color, iridescence, brightness, and polarity. The design of the chromatophore organs and the dermal layer are the focus of this investigation.